1. Field of the Invention
This invention relates to an automatic brake for hose reels and, more particularly, to a hose reel brake which is actuated automatically by a flow of fluid through the hose.
2. Description of the Prior Art
It is known in the prior art to provide braking mechanisms which are employed on various types of reels of general utility, particularly for use as a braking and locking means for hose reels installed on fire and crash trucks. In such applications, it is necessary that the hose, which is also known as a hand line, should always be ready for use by pulling the hose quickly and expeditiously from the reel, but it has been believed necessary that the momentum of the reel be stopped automatically when the desired length of hose has been unwound to prevent over-running of the reel and the unnecessary unwinding of an excessive amount of hose. An example of a prior art hose reel brake is the design disclosed by D. C. Hannay et al in U.S. Pat. No. 2,906,472. The mechanism disclosed therein comprises a horizontal brake control bar that extends across the hose reel in contact with the hose and which is in direct connection with a brake shoe adapted to be actuated into engagement with a brake disc secured on the reel supporting shaft. The arrangement is such that the control bar is operable when the hose is tensioned on being pulled from the reel to permit the brake shoe to assume a nonbraking relation with the brake disc, and with the control bar being otherwise operable when the hose is untensioned to thereby actuate said brake shoe laterally into engagement with the brake disc to provide an automatic braking and locking action on the reel. A further design in the prior art operable by the tension on the hose but which uses a drum-type brake instead of a disc-type brake is disclosed by W. B. Pashkow in the U.S. Pat. No. 2,726,828. The systems of Hannay, et al and Pashkow utilize a hose-tension activated horizontal bar or roller to actuate braking systems of the mechanical type; however, it is also known in the prior art to use similar horizontal bar systems to actuate a pneumatically operated reel brake. These reel air brake systems are generally truck-mounted installations which are supplied with compressed air from the vehicle air brake system.
A disadvantage of these prior art systems is that the horizontal brake control bar or roller results in a cumbersome unwieldy installation that is susceptible to interference with or from adjacent operating equipment. A more serious objection to these hose-tension related systems is that unless the hose is prevented from drooping onto the ground or road when it is being unreeled, there is nothing to stop the roller from dropping, thereby causing the brake to be activated to prohibit the unreeling of any more hose. Considering the weight of the hose, this drooping of the hose and subsequent operation of the brake happens repeatedly, causing problems in drawing out the necessary hose. To permit an unimpeded unreeling of hose, it is generally required to have a man standing by to prevent the unwanted activation of the reel brake.